Developer

• Developer is the chemical that actually makes the image appear on the film by turning the silver halide crystals in the film, which have been exposed to light, to elemental silver. Developer must be mixed with water in the correct amounts first (the ratios are typically found on the developer container). The active ingredients in developer are diethanolamine-sulfur dioxide complex, potassium bromide, sodium bisulfite, and hydroquinone. Color film takes a different developer, as color developer also activates dye coupler chemicals in color film.
  
  

Stop Bath

• Stop bath is used to stop the process of the developer. It is generally made of a solution of water and acetic acid, though some use sodium bisulfite or citric acid. It changes the contents of the can to a non-alkaline solution, washing away and neutralizing the developer.
  
  

Fixer

• Fixer allows the film to be exposed to light without further changing the image on the film. Fixer is usually made from a solution of sodium thiosulfate or ammonium thiosulfate, and it works by removing the remaining silver halide in the image. If fixer is not used, film re-exposed to light will turn dark and become unusable.
  
  

Water

• Water is essential in the process, as it washes away all remaining traces of chemicals from the film. If water is not used, the chemicals will damage the film over time. As not all water is pure, purchase distilled water for use in development.